Light source device and projector

A light source device comprising:

• a light source section configured to emit a first light beam which has a first wavelength band and includes light polarized in a first polarization direction and light polarized in a second polarization direction different from the first polarization direction;
• a first polarization split element which is configured to transmit the first light beam entering the first polarization split element from the light source section along a first direction and polarized in the first polarization direction toward the first direction, and is configured to reflect the first light beam polarized in the second polarization direction toward a second direction crossing the first direction;
• a second polarization split element disposed at the first direction side of the first polarization split element, and configured to transmit the first light beam which enters the second polarization split element along the first direction from the first polarization split element, and is polarized in the first polarization direction toward the first direction;
• a reflecting element disposed at the second direction side of the first polarization split element, and configured to reflect the first light beam which enters the reflecting element along the second direction from the first polarization split element, and is polarized in the second polarization direction toward the first direction;
• an optical element disposed at the first direction side of the reflecting element, and configured to reflect the first light beam which enters the optical element along the first direction from the reflecting element, and is polarized in the second polarization direction toward the second direction;
• a wavelength conversion element which is disposed at the second direction side of the optical element, which is configured to perform wavelength conversion on the first light beam entering the wavelength conversion element along the second direction from the optical element, and polarized in the second polarization direction, and which is configured to emit a second light beam having a second wavelength band different from the first wavelength band toward a third direction as an opposite direction to the second direction;
• and
• a diffusion element disposed at the first direction side of the second polarization split element, and configured to diffuse the first light beam which enters the diffusion element along the first direction from the second polarization split element, and configured to emit the first light beam diffused toward a fourth direction as an opposite direction to the first direction, wherein
• the optical element transmits the second light beam which enters the optical element along the third direction from the wavelength conversion element toward the third direction,
• the second polarization split element transmits the second light beam polarized in the first polarization direction toward the third direction and reflects the second light beam polarized in the second polarization direction toward the fourth direction,
• the first polarization split element reflects the second light beam which enters the first polarization split element along the fourth direction from the second polarization split element and which is polarized in the second polarization direction toward the third direction, and
• the second polarization split element reflects the first light beam which enters the second polarization split element along the fourth direction from the diffusion element toward the third direction.